Steam-generator



(No Model.)

G. A. WAGNER.

STEAM GENERATOR.

Patented Deo. 13,1881.

Wllesse.

.if f 6.9%

N'rnn STATES GASPER A. VAGNER, OF PORTLAND, INDIANA.

STEAM-GENERATO R.

SPECIFICATION forming part of Letters Patent No. 251,006, dated December 13, 1881.

Application filed July 5, 1881.

To all whom it may concern:

Be it known that I, GAsPnR A. WAGNER, a citizen of the United States, residing at Portland, in the county of Jay land State oflndi'- ana, have invented certain new and useful Improvements in Steam-Generators; and I do hereby declare the following to be a full, clear,

and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the saine, reference being had to the accompanying drawings, and to the letters or iigures of reference marked thereon, which form a part of this specification.

My invention relates to improvements in steam-generators in which tubes are employed to increase the heating-surface thereof 5 and the object of my invention is to provide novel means for preventing injury to such generators in the event of the water therein being allowed to fall below a certain point. I attain this object by means of the devices illustrated in the accompanying drawings, in which- Figure l is a sectional elevation of a generator of the locomotive type, showing how it may be constructed and how my improvements may be applied thereto. Fig. 2 is a sectional elevation, showing a portion of the tube-sheet of a steam-generator, nuts and washers or gaskets for securing the tubes therein, the different sections of a tube made according to my plan, and a soft-metal ferrule for uniting the parts of the tube; and Fig. 3 is a sectional elevation of the soft-metal ferrule, the screwthreads in its ends for receiving the outer sections of the tube, and the short central section of tube in position.

Similar letters refer to similar parts throughout the several views.

Various expedients have heretofore been resorted to for the purpose of preventing injury to steam-generators when, through accident or carelessness, the water in them has been allowed to fall to such an extent as to leave the metal composing the crown-sheet of the fire-box or the tubes exposed to too high a degree of heat. The devices used for such purpose have generally consisted of a plug having a hole bored through it, said hole being filled with some kind of metal or an alloy of metals that would melt at a lower temperature than that required (No model.)

to permanently injure the tubes. This method has been found to be deficient as a protector of the tubes, as it has to be placed in positions where the temperature is liable to vary very much from that to Which the tubes are exposed.

My invention is designed to obviate this difficulty by placing the metal to be melted,when occasion occurs, upon the tube or tubes of the generator, and consequently where it is subjected to about the same temperature as is the tube.

My improvement is applicable to all forms of steam-generators in which tubes are employed through which the heated gases pass from the tire-box to the atmosphere, whether they are horizontal or vertical.

The form of generator chosen for the purpose of showing the application of my improvement is of the locomotive type, A referring to such a generator, the ilues or tubes B- B of which pass through the horizontal portion thereof, and are held in tube-sheets cc provided with the requisite apertures for receiving them. One or more of these tubes are made to consist of the sections or parts B', B2, and B3, as shown in Fig. 2, the inner ends of the portions B' and B2 being provided with screw-threads, while the central portion, B3, is a plain ring of metal of any desired length, and of equal diameter with the other sections. This central portion is inclosed in a ferrule, B4, of some form of metal or an alloy ot' metalssuch, for instance, as an alloy made ot' two parts of tin and one of bismuth, or any other alloy or metal that will not melt in the water contained in the generator, but that will melt at a less temperature than that required to injure the tubes. This ferrule may be cast upon the portion B3 of the tube, or it may be secured thereon by having a thread cut upon its inner surface throughout its entire len gth; and thecentralportion,beingprovidedwithathread upon its outer surface, may be screwed upon said portion. In either case there is to be a -thread in each end of the ferrule B, as shown in Fig. 3,' for the reception of the inner ends of the portions B and Bz of the tube B, which are to be screwedV into said ferrule until their ends come in contact with the ends of the centrai portion, B3. When thus constructed the tubes will remain int-act while in use until the IOC temperature to which they are subjected becomes sufficiently high to melt the ferrule B4, when it will disappear, and allow the portion B3 to fall out of its place, which will have the el'ect to allow steam to pass into the fire-box and extinguish the fire, or at least deaden it to such an extent as to prevent an increase of the temperature. The method of securing these tubes in the tube-sheets is clearly shown in Fig. 2, where it will be seen that two nuts, D D', are employed, the former being placed upon the inside of the sheet and the latter outside thereof. Between the nut D and the tube-sheet there is placed a conical gasket or ring, D2, and between the nut D and the sheet a washer of copper. When the tubes have been placed in the sheets the nuts are screwed down upon the washers, which 'forms a tight joint and at the same time holds the tubes in position.

In practice any number oi the ferrules may be used, each tube, it' desired, being supplied with one, as shown in the drawings; but as a rule from one to three will be found sufficient. When used in a vertical generator the proper location of the ferrule or ferrules will be found to be, say, six'inches above the lower tubesheet.

plished will be the same as or similar to that produced when three sections are used.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

A tube for steam-generators, consisting of two or more sections or parts terminating in a ring or ferrule of metal, or of an alloy of metals, the melting-point of which is below that of the tube upon which it is used, it being for the purpose set forth.

In testimony whereof I affix my signature in presence of two witnesses.

GASPER AUGUSTUS WAGNER.

Witnesses:

JAMES H. TrzzoRD, J. A. J AsPEu. 

